During catheter-based procedures, the physician often visualizes the area being treated under fluoroscopy and visualizes the catheter and/or treatment area using radiopaque materials. One method of visualizing is to fabricate the catheter from a polymer that has been compounded with any of the radiopaque materials that are known in the art, such as barium sulfate, bismuth trioxide, bismuth subcarbonate, tantalum and/or other known combination of radiopaque additives. Another known method is to put one or more marker bands around the outer diameter of the catheter at various positions at the distal end of the catheter. The marker bands can be spaced at known distances along the length of the catheter such that a fluoroscopic procedure can be used to determine distances of, for example, a lesion. Contrast dyes also are used to visualize the treated area by injecting a contrast dye through the catheter while the fluoroscope is being operated. The physician then can see the vessel in which the catheter is positioned, as well as any lesion past which the contrast dye flows.
In the procedure, the physician may use a guiding device, such as a guide wire, to controllably reach the lesion or area to be treated. Once the guide wire is in position, the physician may need to pass one or more catheters, tubular devices, and/or medical devices along the guide wire to the lesion or treatment area The physician may pull the catheter or tubular device back along the guide wire and finally off of the guide wire. A difficulty of this, however, is that the guide wire must be very long (i.e., longer than the catheter) in order to pull the catheter off the guide wire without needing to first or also pull the guide wire out of the patient. A known solution to this problem is the use of a rapid exchange configuration in which the distal end of the catheter has a pair of opening into a lumen and through which the guide wire may be passed by inserting the proximal end of the guide wire through the distal most opening and then passing the proximal end of the guide wire out of the proximal opening of the lumen. For example, such a configuration is described by Yock (U.S. Pat. No. 5,451,233), which is incorporated by reference herein in its entirety.
One common application of rapid exchange and marker catheters is during coronary angioplasty, which refers to the use of an inflatable balloon to increase the blood flow through a stenosis (i.e., a partially blocked section of a blood vessel feeding the heart). A typical coronary angioplasty consists of three steps. First, a physician inserts a guiding catheter into a patient's blood vessel, typically through the femoral artery at the top of the patient's leg. The guiding catheter is advanced toward the heart through the patient's blood vessel, stopping short of the coronary arteries, and is then fixed in place. Next, the physician inserts a guide wire into the guiding catheter until the distal end of the guide wire exits the guiding catheter and enters the coronary artery. The physician then positions the guide wire across the stenosis to be treated in the coronary artery, and the guide wire is fixed in place. Finally, the physician advances a balloon catheter along the guide wire until the balloon exits the guiding catheter and is positioned across the stenosis. The physician then inflates the balloon to treat the stenosis, deflates the balloon, and removes the balloon catheter without disturbing the placement of either the guide wire or the guiding catheter.
Physicians frequently need to exchange balloon catheters during a single coronary angioplasty procedure. For example, if a stenosis blocks most of the blood flow through a vessel, the physician may first need to use a small balloon to increase the size of the opening through the stenosis, and then use a larger balloon to further increase the opening. Another example of a catheter exchange is when a physician uses a first balloon catheter to open a lumen and a second catheter to deploy a stent